Hi, Iam looking at putting a large extension on my house. 2 rooms
ground and upper floor. Does anyone know how I work out if my
exsisting boiler will be man enough to heat the additional rooms. I
know I have to find out the overall BTU calculation but how is this
done. Help would be much appreciated.

Dave

wrote:
Hi, Iam looking at putting a large extension on my house. 2 rooms
ground and upper floor. Does anyone know how I work out if my
exsisting boiler will be man enough to heat the additional rooms. I
know I have to find out the overall BTU calculation but how is this
done. Help would be much appreciated.

Dave

You need to do a manual calculation and it involves some work.

The Department of Energy's information on heating and cooling sizing.

http://www.eere.energy.gov/consumer/.../mytopic=12340

--
Joseph Meehan

Dia duit

Dave,

If you add enough insulation, it will reduce the likelyhood that you
will need a new boiler. Get the guy who will be doing the heat piping
for the room addition to do the Manual J load calculation.

Stretch

general ideas:
where? [location affects climate demands.]
age of boiler?
present size of boiler btu?
here's some dumb ideas:
on the coldest day of the winter with the wind chill at its coldest,
does the boiler water satisfy the house zones thermostats now? what
water temperature does it peak at to do that now? depending on the
system's present adjusted limits, what does the boiler's instruction
manual allow for maximum temperature? is there much room left to the
maximum range?
also on our boiler system if the house gets completely cold from an
unreported malfunction, it takes 6 to 8 hours to reheat the house in
winter starting with a cold boiler.
you will run all your separate zone valves and zone thermostats for
each room for efficiency.
otherwise, if you install central air you may be considering a separate
forced air hvac system for the addition.

On 5 Mar 2006 13:45:56 -0800, wrote:

Hi, Iam looking at putting a large extension on my house. 2 rooms
ground and upper floor. Does anyone know how I work out if my
exsisting boiler will be man enough to heat the additional rooms. I
know I have to find out the overall BTU calculation but how is this
done. Help would be much appreciated.

Dave


If you're willing to settle for a rough approximation,
then you measure all the outside surfaces of the projected
house, (So many square feet of wall, so many square
feet of window, so many square feet of door, so many square
feet of ceiling, so many square feet of floor)

Then you find the R values of each of those areas,
invert to get the U value, and multiply by the
square feet for each. Separate out the value for
the floor. Add all the other "U"s together and
call the result X.

Subtract the temperature you want the house to
be at from the temperature of the coldest day
you expect to ever see. Multiply the result
by Y, and call the result Z.

Multiply the "U" for the floor area by the
average temperture for your area, or 45 if
you don't know what the average is. Add
the result to Z. That's the BTU output
you'll need for your furnace.

BTU/H

A BTU is a lump of heat...meaningless by itself. It's the rate BTU's per
Hour that matters.